The present invention relates to vehicle seat underframes, to seats comprising such underframes and to seat assemblies comprising such seats.
More specifically, the invention relates to a vehicle seat underframe comprising:
a rigid framework intended to be fixed to a seat part of a seat and to be mounted to slide in a longitudinal direction on a horizontal rail fixed to the floor of a vehicle, this framework comprising at least one lower guide shoe which projects downwards and which is intended to engage with a longitudinal guide belonging to the said rail,
at least one moving catch which comprises a rigid body stretching between an upper end and a lower end, the lower end of the body of the catch being extended laterally by a projecting claw which extends at the level of the guide shoe in a transverse horizontal direction perpendicular to the said longitudinal direction, the catch being movable with respect to the rigid framework between at least two positions:
a locked position in which the claw of the said catch projects laterally with respect to the guide shoe in the said transverse direction, the claw of the catch then being intended to engage under a rim exhibited by the said rail in such a way as thus to prevent the seat from being removed from this rail, the catch being urged elastically towards its locked position,
and a retracted position in which the claw is moved towards the guide shoe with respect to the locked position, the claw then being intended no longer to interfere with the said rim of the rail and thus to allow the underframe to be removed from this rail,
and an operating device designed to move the catch at least between its locked position and its retracted position, the operating device comprising at least one actuating member which is movable between first and second positions corresponding respectively to the locked position and to the retracted position of the catch.
Document EP-A-0 925 996 describes an example of such a seat, which is entirely satisfactory.
It is a particular object of the present invention to improve seats of the kind in question still further.
To this end, according to the invention, a seat of the kind in question is characterized in that the operating device further comprises a release finger constituting a separate part from the catch, this release finger being mounted to pivot with respect to the framework of the underframe about a release finger pivot, the said release finger comprising a first branch which extends from the said release finger pivot as far as a free end and a second branch which extends from the said release finger pivot as far as a free end, the release finger being movable between:
an effaced position in which the second branch of the said release finger is designed to be raised enough for the said second branch not to interfere appreciably with the rail on which the underframe is intended to be mounted,
and an active position in which the free end of the second branch projects downwards from the framework of the underframe so that when the guide shoe of the underframe is engaged with the longitudinal guide of the rail, the rail lifts the free end of the second branch of the release finger and returns the said release finger to the effaced position, the release finger being urged elastically towards its active position,
in that when the release finger is in the effaced position, the first branch of the said release finger is designed to bear against a cam surface belonging to a release cam connected to the actuating member, as long as the actuating member is not in its second position, then holding the release finger in its effaced position,
and in that the release finger is designed so that when the said release finger is in its active position, the free end of the first branch of the release finger comes into abutment against an abutment face integral with the release cam, thus holding the actuating member of the operating device in its second position.
By virtue of these arrangements, when the seat to which the underframe belongs has been removed from the vehicle, it is particularly simple to fit this seat back in the vehicle. What happens is that all that is required in order to achieve this is for the guide shoes of the underframes of the seat to be inserted vertically in the rails fixed to the floor of the vehicle: the release fingers of each of the underframes then move up into their effaced position, allowing the catch of each of the underframes to return to the locked position.
In some preferred embodiments of the invention, recourse may also possibly be had to one and/or other of the following arrangements, which may possibly be used independently of the arrangements described hereinabove:
the abutment face of the release cam is connected by a rounded portion to the cam surface of the said release cam, and the actuating member is urged elastically towards its first position by at least one spring which is powerful enough that when the free end of the first branch of the release finger comes into contact with the said rounded portion in the absence of external actuation of the actuating member, the spring urging the actuating member drives the said actuating member with the said release cam into the first position and brings the cam surface of the release cam into contact with the first branch of the release finger;
the second branch of the release finger extends at an angle in the longitudinal direction and downwards at least when the release finger is in its active position;
the framework of the underframe comprises two horizontal sliding shoes oriented downwards and intended to bear on a sliding surface belonging to the rail, the free end of the second branch of the release finger projecting downwards beyond the said sliding shoes when the release finger is in the active position, between these sliding shoes;
the release cam is integral with an abutment zone against which the first branch of the release finger angularly abuts when the said release finger is in its active position;
the release cam is integral with the actuating member, which is mounted to pivot about a first axis of rotation parallel to the transverse direction;
the release cam is integral with a pivot cam which collaborates with a first cam follower integral with the catch, the said pivot cam being designed to press against the said first cam follower by causing the catch to pivot about a pivot axle parallel to the longitudinal direction, from its locked position to its retracted position when the actuating member passes from its first position to its second position, the said catch being urged in the opposite direction by a catch spring;
the first cam follower of the catch has an upper bearing surface against which the pivot cam (85) bears to cause the catch to pivot, this upper bearing surface being laterally offset with respect to the rotation axle of the catch;
the actuating member of the operating device is secured to a locking cam and the catch is mounted to pivot on the framework of the underframe with a certain vertical play, between the locked position and a sliding position situated below the locked position, the locking cam coming to bear under a second cam follower situated towards the upper end of the body of the catch so as to hold the catch in its locked position as long as the actuating member is in an angular position lying between its first position and a third position intermediate between the first and second positions, and the said locking cam being designed to allow the catch to drop into its sliding position when the actuating member is in its third position;
the locking cam is in the form of a rigid platelet stretching in a vertical plane roughly parallel to the body of the catch, the said locking cam comprising a slot in which there is engaged a peg integral with the catch, the said slot being shaped to press against the said peg and cause the catch to drop into its sliding position when the actuating member is in an angular position between its third and second positions;
the second cam follower of the catch comprises a rim stretching downwards, the locking cam penetrating between this rim and the body of the catch at least when the catch is in the locked position;
the locking cam is in contact with the rim of the second cam follower, without clearance, when the catch is in the locked position;
the rim of the second cam follower and the locking cam are shaped to collaborate with one another via a cam effect so as to cause the catch to pivot from its retracted position into its sliding position when the actuating member pivots from its second angular position to its third angular position;
the locking cam has a chamfer which collaborates with an angled interior face belonging to the rim of the second cam follower of the catch so as to move the said catch from its retracted position to its sliding position when the actuating member pivots from its second angular position to its third angular position;
the actuating member comprises a metal shaft which is integral with the locking cam, the release cam and pivot cam being integral with a hollow shaft which is fitted over the metal shaft and which is not connected in terms of rotation directly to the said metal shaft, the hollow shaft having end tabs which collaborate by fitting-together with a first operating member that can be actuated by a user, immobilizing the said hollow shaft in terms of rotation with respect to the first operating member, the said first operating member having a notched hole into which a free end belonging to the actuating member penetrates, the said free end being crimped into the said notched hole, thereby securing the said first operating member to the metal shaft;
the actuating member is integral with a first operating member that can be actuated by a user, which allows the said actuating member to be moved between its first and second positions, the actuating member also being mechanically connected to a pinion which is in mesh with a ring of teeth secured to a second operating member that can be actuated by a user, this second operating member being movable in rotation about a second axis of rotation parallel to the first axis of rotation between a rest position and an abutment position corresponding respectively to the first and third positions of the actuating member, the second operating member coming into contact with an abutment integral with the framework of the underframe when the said second actuating member is in its abutment position, and the pinion being connected, with a certain amount of backlash, to the actuating member, so that the said actuating member can pivot from its third to its second position in a first angular direction while the second operating member remains bearing against the corresponding abutment integral with the framework of the underframe;
the pinion is urged elastically in the first angular direction so as normally to be kept bearing angularly against an abutment integral with the actuating member;
the claw of the catch has a free end provided with teeth which project upwards and which are aligned in the longitudinal direction;
there are at least three teeth on the catch, the claw of the catch stretching between a front end and a rear end, and the teeth of the said claw having heights which decrease from the front end towards the rear end of the claw;
the catch is movable downwards from its locked position into a sliding position, the underframe further comprising an abutment claw which is mounted to pivot with respect to the framework of the underframe between an active position and an effaced position, the abutment claw projecting laterally with respect to the guide shoe parallel to the claw of the catch when the said abutment claw is in the active position, the said abutment claw also being shaped to have an upper surface situated above the upper ends of all the teeth of the catch when the said catch is in the sliding position, the abutment claw being urged elastically towards its active position in which it butts angularly against an abutment member integral with the framework of the underframe, and the said abutment claw comprising a part which projects in the longitudinal direction against a face of the body of the catch situated on the opposite side to the claw of the catch, so that the said catch drives the abutment claw from its active position into its effaced position when the catch moves from its sliding position to its retracted position;
the abutment claw is shaped not to extend laterally beyond the claw of the catch at least when the catch is in the retracted position;
the framework of the underframe comprises an additional guide shoe aligned with the said guide shoe in the longitudinal direction, the catch and the abutment claw being arranged between the two guide shoes and being designed to lie roughly in line with the said guide shoes when the catch is in the retracted position;
the claw of the catch has a free end extended upwards by a rim which has a horizontal upper edge running in the longitudinal direction between two inclined ends which extend downwards one opposite the other at the front and rear ends of the claw, each of the front and rear ends of the claw being provided with a catching tooth which has a vertical stop face facing towards the said rim and an upper face arranged at an angle downwards and towards the corresponding end of the claw.
Moreover, another subject of the invention is a vehicle seat comprising a backrest and a seat part mounted on two front underframes and two rear underframes as defined hereinabove, that is to say comprising at least some of the technical characteristics described hereinabove.
Advantageously:
the actuating members of the two front underframes are joined together and the actuating members of the two rear underframes are joined together, the actuating members of the front underframes and of the rear underframes being joined together by an operating linkage;
the linkage is connected with play to the actuating members of the front and rear underframes, this play being chosen so that movement of the actuating members of the front underframes from their first to their second position gives rise to an identical movement of the actuating members of the rear underframes, whereas movement of the actuating members of the rear underframes from their first to their second position does not give rise to movement of the actuating members of the front underframes;
the operating linkage is connected to the operating member of one of the rear underframes and to the pinion of the corresponding front underframe.
Finally another subject of the invention is a vehicle seat assembly comprising a seat as defined hereinabove and two parallel rails running in the said longitudinal direction and each provided with a guide against which the guide shoes of the underframes slide and with a rim under which the claws of the catches of the underframes engage.